In this study we have examined 532 migrant farm workers engaged mainly in the cultivation of vegetable crops, in both greenhouses and openfarms, and an equal number of controls.

Erythrocyte acetylcholinesterase activity (AChE) was measured to determine the degree of toxicity due to exposure to organophosphate and carbamate pesticides in the farm workers employed either as foremen (41.5%) or farmers (58.5%). The mean ages of the farm workers and controls were 35.2 ± 7.4 (mean ± SD) years and 34.6 ± 7.1 years.